From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB829C43387 for ; Wed, 16 Jan 2019 05:08:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7860D20866 for ; Wed, 16 Jan 2019 05:08:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547615316; bh=fPhLoo+uN7CUBdGagJH4t5dtJtwNwNOiw9X3hH4RdZY=; h=From:To:CC:Subject:Date:List-ID:From; b=lPO2A622bA+1RRC0/gGaW/s4anSvZVfmCrFzMpcOoPL3Pz8ZWDBiqpHKu8nU0zUfT /lZ2Vkp57hM5lHIeRMRMpSclGiE9N+nrpadGe6RIeD6tN760GyRAhlCPZagAID6A7q i50SO60TdxLWu7FvevrCNFN1XVwV98Aqwbfu4rik= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726684AbfAPFIf (ORCPT ); Wed, 16 Jan 2019 00:08:35 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:36236 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726556AbfAPFIe (ORCPT ); Wed, 16 Jan 2019 00:08:34 -0500 Received: from pps.filterd (m0089730.ppops.net [127.0.0.1]) by m0089730.ppops.net (8.16.0.27/8.16.0.27) with SMTP id x0G54MpW029615 for ; Tue, 15 Jan 2019 21:08:32 -0800 Received: from maileast.thefacebook.com ([199.201.65.23]) by m0089730.ppops.net with ESMTP id 2q1wmk82sb-12 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Tue, 15 Jan 2019 21:08:32 -0800 Received: from mx-out.facebook.com (2620:10d:c0a1:3::13) by mail.thefacebook.com (2620:10d:c021:18::171) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1531.3; Tue, 15 Jan 2019 21:08:31 -0800 Received: by devbig007.ftw2.facebook.com (Postfix, from userid 572438) id 074F5760B4B; Tue, 15 Jan 2019 21:08:30 -0800 (PST) Smtp-Origin-Hostprefix: devbig From: Alexei Starovoitov Smtp-Origin-Hostname: devbig007.ftw2.facebook.com To: CC: , , , Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH bpf-next 0/9] introduce bpf_spin_lock Date: Tue, 15 Jan 2019 21:08:21 -0800 Message-ID: <20190116050830.1881316-1-ast@kernel.org> X-Mailer: git-send-email 2.17.1 X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-01-16_01:,, signatures=0 X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Many algorithms need to read and modify several variables atomically. Until now it was hard to impossible to implement such algorithms in BPF. Hence introduce support for bpf_spin_lock. The api consists of 'struct bpf_spin_lock' that should be placed inside hash/array/cgroup_local_storage element and bpf_spin_lock/unlock() helper function. Example: struct hash_elem { int cnt; struct bpf_spin_lock lock; }; struct hash_elem * val = bpf_map_lookup_elem(&hash_map, &key); if (val) { bpf_spin_lock(&val->lock); val->cnt++; bpf_spin_unlock(&val->lock); } and BPF_F_LOCK flag for lookup/update bpf syscall commands that allows user space to read/write map elements under lock. Together these primitives allow race free access to map elements from bpf programs and from user space. Key restriction: root only. Key requirement: maps must be annotated with BTF. This concept was discussed at Linux Plumbers Conference 2018. Thank you everyone who participated and helped to iron out details of api and implementation. Patch 1: bpf_spin_lock support in the verifier, BTF, hash, array. Patch 2: bpf_spin_lock in cgroup local storage. Patches 3,4,5: tests Patch 6: BPF_F_LOCK flag to lookup/update Patches 7,8,9: tests Alexei Starovoitov (9): bpf: introduce bpf_spin_lock bpf: add support for bpf_spin_lock to cgroup local storage tools/bpf: sync include/uapi/linux/bpf.h selftests/bpf: add bpf_spin_lock tests selftests/bpf: add bpf_spin_lock C test bpf: introduce BPF_F_LOCK flag tools/bpf: sync uapi/bpf.h libbpf: introduce bpf_map_lookup_elem_flags() selftests/bpf: test for BPF_F_LOCK include/linux/bpf.h | 39 +- include/linux/bpf_verifier.h | 1 + include/linux/btf.h | 1 + include/uapi/linux/bpf.h | 8 +- kernel/bpf/arraymap.c | 23 +- kernel/bpf/btf.c | 37 ++ kernel/bpf/core.c | 2 + kernel/bpf/hashtab.c | 48 ++- kernel/bpf/helpers.c | 53 +++ kernel/bpf/local_storage.c | 16 +- kernel/bpf/syscall.c | 48 ++- kernel/bpf/verifier.c | 139 +++++- net/core/filter.c | 16 +- tools/include/uapi/linux/bpf.h | 8 +- tools/lib/bpf/bpf.c | 13 + tools/lib/bpf/bpf.h | 2 + tools/lib/bpf/libbpf.map | 4 + tools/lib/bpf/tags | 254 +++++++++++ tools/testing/selftests/bpf/Makefile | 2 +- tools/testing/selftests/bpf/bpf_helpers.h | 4 + tools/testing/selftests/bpf/test_map_lock.c | 66 +++ tools/testing/selftests/bpf/test_progs.c | 117 ++++- tools/testing/selftests/bpf/test_spin_lock.c | 108 +++++ tools/testing/selftests/bpf/test_verifier.c | 429 ++++++++++++++++++- 24 files changed, 1411 insertions(+), 27 deletions(-) create mode 100644 tools/lib/bpf/tags create mode 100644 tools/testing/selftests/bpf/test_map_lock.c create mode 100644 tools/testing/selftests/bpf/test_spin_lock.c -- 2.17.1